1. Field of the Invention
The present invention generally relates to electric circuit breakers and, more particularly, to a new high-current, solid-state DC circuit breaker in which both the switch and the tripping circuit are solid-state.
2. Background Description
Mechanical circuit breakers are dominant in the prior art. A full range of mechanical circuit breakers are available from a variety of manufacturers with voltage ratings up to 550 kV and current ratings up to 63 kA. Mechanical circuit breakers take milliseconds to interrupt current and generate an arc during the turn-off transient.
There are some so-called solid-state circuit breakers on the market, but the actual circuit breaker is mechanical, only the tripping circuit is solid-state. For example, a hybrid circuit breaker manufactured by Mitsubishi Electric Power Products, Inc., under the trade names Light Speed™ SSTS & Light Speed™ SSB is implemented with a vacuum switch and highly rated thyristor elements. The response time of this hybrid circuit breaker is limited by the mechanical vacuum switch. The Light Speed™ SSTS circuit breaker is capable of less than quarter-cycle energy transfers, while the Light Speed™ SSB circuit breaker provides half-cycle circuit interruptions. Toshiba Power Electronics Equipment manufactures a thyristor rectifier/thyristor inverter/gate turn-off thyristor (GTO) circuit breaker capable of 1500V/7500A rating, but requires a half-cycle (>8 ms) to turn-off the fault current.